Heat domes, Anticyclones and climate change: What’s causing heat waves across the world?

  • The US scientific and regulatory agency National Oceanic and Atmospheric Administration (NOAA) recently announced that the June was the Earth’s hottest month since the record-keeping of global temperatures began 174 years ago.
  • The average daily global temperature was recorded at 17.12 degree Celsius.
  • But, this isn’t the temperature of one place or region but a measure of average over both land and ocean, including the ice sheets in the polar region and the snow of the high mountains where surface temperatures are well below zero degree Celsius.

Factors responsible for temperatures rise in different parts of the world

  • While El Nino conditions, which have developed for the first time in seven years, are partly responsible for triggering extreme heat, continents like North America, Africa, Asia and Europe have been faced intense heat waves which are caused by either formation of heat domes or arrival of anticyclones.
  • Not only this, record high sea surface temperatures have also worsened the situation.
  • Apart from it, the present crisis is climate change, which has increased the frequency and intensity of extreme weather events like heat waves and mass scale floods.

Global situation

  • Most parts of the world are currently experiencing intense heat due to the onset of heat waves but their cause remains different across regions.
  • While in the USA and Algeria, heat domes are responsible for unleashing heat waves, Europe has suffered due to the arrival of two consecutive anticyclones that originated in Africa.


  • It is also known as a high-pressure system.
  • It is essentially an area of high pressure in which the air goes downwards towards the Earth’s surface.
    • As the air sinks, its molecules get compressed, which increases the pressure, making it warmer.
    • This causes dry and hot weather.
    • The winds remain calm and gentle during an anticyclone, and there is almost no formation of clouds because here the air sinks rather than rises.

Heat dome

  • Occurs when an area of high-pressure stays over a region for days and weeks.
  • It traps warm air, just like a lid on a pot, for an extended period.
    • The longer that air remains trapped, the more the sun works to heat the air, producing warmer conditions with every passing day.
    •  Heat domes, if they last for a long period, may cause deadly heat wave.
  • Although heat domes and anticyclones don’t occur due to climate change, they have become more intense and longer as a result of soaring global temperatures

Impact of Green house gases emissions

  • As the planet continues to get warmer due to unprecedented levels of greenhouse gases being released into the atmosphere, extreme weather events, much like those unfolding right now, will become more frequent.
  •  Moreover, if the Earth breaches the 1.5-degree Celsius global warming limit by the 2030s, there may be irrevocable damage to the ecosystem and geology, humans and other living beings, severely impacted.

Role of El-Nino in global temperature rise

  • El Nino conditions are exacerbating the extreme heat around the world.
  • It is a weather pattern that refers to an abnormal warming of surface waters in the equatorial Pacific Ocean, El Nino is known to “greatly increase the likelihood of breaking temperature records and triggering more extreme heat in a lot of different parts of the world and in the ocean,

Heat waves

  • Heat waves are particularly lethal when high temperatures combine with high humidity, which is commonly referred to as a wet bulb
  • In such conditions, sweat from the human body isn’t able to evaporate, failing to stabilise the body temperature, which could ultimately cause heat stroke  it takes place only when the body temperature goes above 40 degrees Celsius  and even death.
  • Last month, more than 60 people died in Uttar Pradesh’s Ballia after the region was hit by a heat wave. 

The worst affected countries

  • The WMO recently said the country’s southern, western and mid-western regions will continue to simmer in the following days, partly also due to unusually warm waters in the Gulf of Mexico and in the western Atlantic Ocean that would exacerbate humidity in coastal areas and thwart nighttime cooling.
  • Meanwhile, hot temperatures have sparked numerous wildfires in South California.
  • Similarly, flames have erupted in neighbouring Canada.
  • In Asia, China, Iraq and Saudi Arabia remain some of the worst affected countries.
  • Most significantly, a remote township in China saw temperatures touching 52 degree Celsius on July 16 — shattering the previous record of 50 degree Celsius that was set in 2015.


  • Because of this, people all over the world will experience changes in their access to water, their ability to produce food, their level of health, and the quality of the environment they live in. 
  • In addition, the rate of warming caused by global warming is accelerating. If we are unable to stop it as quickly as possible, our world will be subject to consequences that are not desirable.
  • Therefore, there is need for a collective and inclusive efforts by nations at the national and global level to counter the effect of climate change.